NWS Forecaster Discussion

Southwest California area forecast discussion
National Weather Service Los Angeles/Oxnard California
1041 am PDT sun Aug 2 2015
Synopsis... a nearly stationary upper level low off the coast will
promote near to just below normal daytime temperatures with
overnight to morning clouds and patchy fog for the coast and
adjacent valleys. The low will move through the region by late in
the week to bring slightly cooler temperatures.
&&
Short term (rest of today-wed)... latest prieps show marine layer
depth is about 1700 feet south and slightly deeper north. Our onshore
pressure gradients are a little weaker this morning but not enough
to change the timing of the coastal stratus clearing so expect the
usual morning burn off. A little cooler this morning far inland
sections but overall expect highs across the region today to be
pretty close to yesterday's if not a couple degrees cooler.
Localized sundowner winds are likely again tonight and Monday night
in the western half of the sba South Coast. Gusts at the Refugio
RAWS site gusted to 45 miles per hour last night and high-res models indicate
slightly stronger winds tonight and tomorrow night.
Not much change through the period...possibly a brief bump up in
temperatures on Wednesday and a shallower marine layer under some ridging
in advance of the dry upper low that will move through later in the
week.
***From previous discussion***
Long term (thu-sat)... an weak and dry upper low approaches the
area Thursday but not in time to affect the weather. Perhaps a
little pop up ridge ahead of it will raise the inland temperatures a degree
or two.
The upper low moves over the area Friday and Sat. It is not a rain
maker...perhaps a drizzle maker. Its main effect will be to increase
the marine layer and night through morning stratus should cover all
the coasts and most of the valleys. The deeper marine layer and lower
heights will kick off a cooling trend.
&&
Aviation...02/1800z...
Middle/upper level trough axis oriented northwest-southeast and centered south of the
area will shift north over the area. Upper level light to moderate
and relatively dry south winds will become moderate southwest while
middle level dry light and variable winds become light southwest by
03/07z. Weak to moderate onshore pressure gradient through 03/02z
and after 03/20z otherwise weak north and onshore gradient. Marine
inversion with a base approximately 1.8kft the morning will differ
little Monday morning. Marine cloud field was unorganized this
morning and expect little difference Monday morning.
Marine layer at lax at 1500z is 1877 feet deep and the inversion top
is at 2825 feet with a temperature of 24.6 degrees c.
Klax...chance ceilings 007 between 03/07-03/10z and ceilings 013 between
03/10-03/18z.
Kbur...chance ceilings 010 after 03/11z
Virtually certain - 95-100%
very likely - 80-95%
likely - 60-80%
chance - 30-60%
very unlikely - 20% or less
&&
Marine...02/900 am...
Small Craft Advisory conditions with northwest winds and very steep
seas will persist from Point Conception to south of San Nicolas
Island through Wednesday morning. There is a chance Small Craft Advisory conditions
with northwest winds will exist from Piedras Blancas to Point Sal
this afternoon through this evening and Monday afternoon through
Monday evening. And there is a chance Small Craft Advisory conditions will exist in
the west half of the Santa Barbara basin and in the vicinity of
Santa Cruz Island this afternoon and each afternoon Monday through
Wednesday.
&&
Lox watches/warnings/advisories...
Small Craft Advisory (see laxmwwlox).
&&
$$
Public...Jackson/rorke
aviation/marine...30
synopsis...Munroe
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